Fullerenes are hollow molecules composed of pure carbon atoms. Typically, fullerenes each have 12 pentagons, but differing numbers of hexagons. The pentagons are required in order to allow curvature and eventual closure of the closed surface upon itself. The most abundant species to date is the C.sub.60 molecule or Buckminster Fullerene. C.sub.60 consists of 12 pentagons and 20 hexagons and is classified as an icosahedron, the highest symmetry structure possible. The second most abundant species, C.sub.70, contains 12 pentagons and 25 hexagons. To date, fullerenes containing up to 400 carbon atoms have been identified. Characteristic of fullerenes is their general formula C.sub.2n where n is greater than or equal to 25.
Fullerenes are produced by high temperature vaporization of solid graphite rods by resistive heating or arc heating in the presence of a few to several torr of rare gas. The soot produced by the vaporization contains varying levels of fullerenes, depending on the vaporization conditions. However, the majority of the fullerenes produced are C.sub.60 and C.sub.70, with C.sub.60 being more abundant.
The fullerenes are extracted from the soot by placing the soot into a solvent in which the fullerenes are soluble. The solution is then filtered and allowed to evaporate to yield fullerene powders. Alternatively, the fullerenes can be purchased commercially.